i dont know if you could fit a brushless motor in a 12th scale with the way the rear pod works (maybe on a trinity car though...) although a brushless in a 12th scale is completly unessary for many reasons....
racerdx- i got to run the ascari bodies for the first time at the paved nats last week and found that they hold up the best out of all the lightweight bodies out there currently. as far as cutting out the body so it doesnt rub the tires or chunk em after a hit, here is what to do. in step form!
1)mount the body, just make holes for the posts, and lock the body in as if you were to go racing with body clips.
2) find the axle line (or center of the wheel when the car is sitting with batteries and everything, basically ready to go), and then make a dot with a sharpe.
3)take a spare tire (with the same diamiter or slightly larger) place the center of the spare tire where that dot was and take the sharpe and trace it, then cut out the line. however near the bottom make sure to open it up. basically you want to make sure that within the travel that the wheel will go through during racing that the tire will not contact the body in any way. so make sure that when the lexan before and after the tire is turned in it doesnt get stuck on the tire.
4)for achieving the proper body height, go back to step one (or you could do this before cutting out the wheels, it doesnt matter). place the car on a level surface (like a table) and then lay the sharpe flat on the ground, then take the sharpe and run it around the body. you should end up with a line 3mm or so above the ground, if you cut that line then your body will be at the perfect height to the ground. (sometimes it takes a few times to make sure it is correct if the body has to much material below the chassis). also make sure to do this with the correct ride height and tire size, since if you mount the body too low the tires might rub.
5) with the front tires to make sure they dont rub the body... put the body on the car and then turn the wheels and compress the suspenion to make sure that the front tire will not rub the body during its movement during racing.